Method for the production of a plate heat exchanger

A method of manufacturing a plate heat exchanger from a plurality of individual plates joined together to form a plate stack having a stacking direction, the method at least comprising the following method steps:

• providing metal sheets having flat large surfaces,
• forming individual plates by bending each of the metal sheets exclusively along one marginal edge running in a longitudinal direction, whereby a seam running in the longitudinal direction is formed per metal sheet and a free unbent marginal edge running in the longitudinal direction is retained opposite of the seam,
• forming a plate pair by arranging two individual plates, each in the form of one of the previously bent metal sheets, one on top the other in the stacking direction of a later plate stack and welding the previously bent metal sheets together, the two individual plates being turned towards each other with their respective seams in such a way that the seam of the first individual plate is assigned to the free unbent marginal edge of the second individual plate and that the seam of the second individual plate is assigned to the free unbent marginal edge of the first individual plate and the two individual plates being welded together along their respective seams and the free marginal unbent edges cooperating therewith, and
• forming a plate stack by arranging at least two plate pairs one on top of the other in the stacking direction of the later plate stack and welding the at least two plate pairs together, the two plate pairs being arranged one on top the other with the interposition of a first spacer extending along a first longitudinal edge and a second spacer extending along a second longitudinal edge, and the spacers being welded together with the respective plate pairs adjacent thereto,
• wherein at least two first flow channels for a first medium and at least one second flow channel for a second medium are being formed, wherein each first flow channel is formed between the two individual plates of each plate pair and the second flow channel is being formed between the two plate pairs and the first and the second spacer, arranged between the two plate pairs, whereby two opposite and longitudinally extending side walls of the second channel are formed by the first and the second spacer respectively,
• wherein the elongate spacers are used which have at least one of an L-shaped cross-section, a C-shaped cross-section and a complex cross-section.